Evil casts a long shadow over BBC America's promising new thriller Ripper Street (Saturday, 9/8c). Set amid the grimy slums of London's Whitechapel district in the immediate wake of Jack the Ripper's reign of slaughter, this absorbing 19th-century procedural depicts police work complicated by widespread public panic that each new murder might herald the return of the phantom fiend.

"It is to our uniform that they direct their fury," laments level-headed Inspector Edmund Reid (the excellent Matthew Macfadyen) about the vigilante mob mentality that makes their jobs more difficult and the already mean streets even more dangerous. Reid bears scars, both physical and emotional, from his futile pursuit of the Ripper, as do his colleagues Drake (Jerome Flynn), a bruiser who fights his way to the truth, and the American transplant Jackson (Adam Rothenberg), a former Army surgeon whose cutting-edge forensic knowledge comes in handy — if he can pull himself away from the booze and the fallen women long enough to focus.

In its gritty and sordid period details, Ripper Street has a surface similarity to last summer's homegrown Copper, but is much better acted and gets off to a far stronger start with a lurid case that sends the local tabloids into an "Is it HIM? Is it JACK?" frenzy. When Inspector Reid confronts a vulture journalist fanning the flames of sensation, he protests on behalf of the public, "They need their fears pacified." The response: "Where would be the sport in that?" Ripper Street is mighty fine bloodsport.

SAVING THE WORLD: It's a messy, risky and thankless job, but those hardy heroes of Fox's Fringe Division are up to the challenge one last time, in a two-hour climax (Friday, 8/7c) pitting the resistance fighters against those bald-meanie Observers. The finale wasn't made available for preview, but the gripping trailer promises a powerfully emotional conclusion to a remarkable if low-rated five-season run that defied the odds by returning season after mold-breaking season, reinventing itself along the way with little regard for ratings, instead driven by a desire to challenge its passionately devoted cult audience. I'll miss them all, but like they said about the scarecrow in The Wizard of Oz, I'll miss the mercurial, lovable, tormented mad scientist Walter Bishop (John Noble) most of all.

DVR alert in the same time period for another fringe favorite: The CW's Nikita(Friday, 8/7c), which picks up from its December cliffhanger with a pivotal nail-biter, in which the Division team reels from the news that Birkoff's beloved fellow techie Sonya is Amanda's mole — yes, there's always a mole, and in this sleekly convoluted spy thriller, they rarely stop with one. Sonya has a "kill chip" in her skull that Amanda could trigger at the slightest hint that anything's amiss back in her old digs, and while Birkoff desperately schemes how to keep Sonya off the grid long enough to deactivate the device, Nikita and Michael seek out the legendary "Watchman" who's been keeping shadowy tabs on them. Complicating the mission: Alex's relapse into addiction with painkillers. By the end of the episode, one of the key players is going to need those drugs in a big way.

Pills with a deadly side effect play a major role in the second episode of Cinemax's Banshee (Friday, 10/9c), as convict-turned-Sheriff Lucas Hood (Antony Starr) raids a rave being held in an Amish barn, where a tainted batch of E sends shock waves through the community.

WHAT ELSE IS ON FRIDAY: Yet another drug subplot, this time on CBS' Blue Bloods (10/9c), involving the embattled detective Danny Reagan (Donnie Wahlberg), who's taken into custody when cocaine is found in his trunk. The episode is titled "Framed," which the rest of the family will need to prove. ... HBO's provocative Real Time With Bill Maher returns for an 11th season of outspoken political and cultural debate, with guests including former Nebraska Sen. Bob Kerrey and comedian Martin Short. What are the odds that gun control legislation will come up?

SATURDAY NIGHT AT THE TV-MOVIES: Rob Lowe is back on Lifetime (home of his camp classic Drew Peterson: Untouchable), this time on the side of justice, as Florida assistant state attorney Jeff Ashton in Prosecuting Casey Anthony (8/7c), reliving the sensational trial and wondering what went wrong with the verdict. ... He can skate and dance, but can he act? Probably doesn't matter, as Olympian Apolo Ohno appears alongside former Wonder Years ingénue Danica McKellar in Syfy's latest Saturday night creature-feature opus, Tasmanian Devils (9/8c). ... Cold Case's Kathryn Morris returns to TV in Hallmark Channel's The Sweeter Side of Life (9/8c) as a newly divorced doctor's wife who leaves Manhattan for her dad's New Jersey bakery, where she learns to love a different sort of dough.

WHAT ELSE IS ON SATURDAY: Golden Globe winner Jennifer "I beat Meryl" Lawrence (Silver Linings Playbook, The Hunger Games) would seem to have the proper moxie to be a host worth watching on NBC's Saturday Night Live (11:30/10:30c), with The Lumineers as musical guest. ... Ricky Gervais once again sends his favorite stooge Karl Pilkington packing on a third season of Science Channel's An Idiot Abroad (9/8c), this time in the company of Life's Too Short star Warwick Davis. Their new itinerary follows Marco Polo's trajectory from Italy to China. ... This is followed by the new comedy-infotainment hybrid Stuff You Should Know (10/9c), based on the popular podcast.

WHAT'S ON SUNDAY: Besides football, you mean? (Expect huge numbers for Fox's broadcast of the NFC championship in the afternoon and CBS' showing of the AFC title game, which takes over much of the prime-time schedule.) ... Two of last weekend's Golden Globe winners resume their second seasons. On HBO's Girls (9/8c), Hannah's (Lena Dunham) new beau tells her what he really thinks of her writing, and let's just say it doesn't merit another acceptance speech. ... On Showtime's House of Lies (10/9c), Marty (Don Cheadle) and his randy posse go to Las Vegas to restore a fading casino's image. Something tells me they'll be right at home in Sin City. ... There's a new footman turning heads on PBS' Downton Abbey (check tvguide.com listings), and a surprise fugitive from Ireland, while poor jilted Lady Edith finds her voice and purpose in the cause of women's suffrage. ... Of the major broadcast networks, only ABC is airing original episodes (although the failed experiment of double-running sitcoms Happy Endingsand Don't Trust the B---- in Apartment 23 has ended abruptly, the time period handed over to a Shark Tank repeat at 10:02/9:02c). On Once Upon a Time (8/7c), Storybrooke debates what to do with the stranger who crashed his car after driving into the magic city. And on Revenge (9/8c), Daniel faces off with a business rival (Dylan Walsh). ... Following the AFC game, CBS airs a special Hawaii Five-0 (approximately 10/9c), in which a kidnapped Chin Ho (Daniel Dae Kim) finds himself behind bars in prison duds, not the safest situation for a Five-0 agent. The soundtrack features several unreleased tracks by Jimi Hendrix, who would have been 70 this year. ... Another legend is celebrated on Turner Classic Movies, marking musical-comedy great Danny Kaye's centennial with a daylong marathon of 11 films, plus TV highlights from the '60s variety show The Danny Kaye Show (6 am/5c) and a 1971 appearance on The Dick Cavett Show (10:30 a.m./9:30c).